(physics) The transition between thermodynamic phases of a physical system, especially one between the solid, liquid, and gaseous phases of a substance.

(physics) One of the three fundamental structural phases of matter in which the thermal mobility of molecules or atoms is strong enough to permit their free motion, significantly exceeding the cohesive force.

(physics) One of the three fundamental structural phases of matter in which the cohesive force of matter is strong enough to keep the molecules or atoms in the given positions, restraining the thermal mobility.

(physics) One of the three fundamental structural phases of matter in which the thermal mobility of molecules or atoms is comparable with the cohesiveness, having them connected but fluid in a mass.

(astronomy) Any one of the aspects or appearances presented by the moon as seen from Earth.

A method of sending information by modifying (modulating) the difference in phase (fraction of a wave length) between a signal and a reference.

A small yellow-brown ant, Monomorium pharaonis, introduced to virtually every area of the world, considered to be a major indoor pest.

(often attributive) A standard of purity suitable for medicinal use.

(electricity) Differing in phase by a quarter of a cycle; two-phase.

A microscope that uses the change of phase when light is transmitted or reflected from a transparent or reflective specimen to form an image; used especially to study living cells.